Barack Obama and Bill Clinton on the campaign trail in 2012. Both men have plenty at stake in this year's midterms. Photograph: Jewel Samad/AFP/Getty Images

Not one, but two, Democratic presidents met with their party's senators on Wednesday at a private strategy meeting about an election year that could prove almost as pivotal as the race for the White House in 2016.

Barack Obama and Bill Clinton have plenty at stake in making sure their party does not lose its narrow control of the Senate in November's midterm elections. Obama needs to hold the upper chamber, in which the Democrats currently have a 55-45 advantage, if he is to have any chance of passing legislation in his increasingly moribund second term. A Senate majority would be equally vital to Hillary Clinton if she runs for, and wins, the presidency in 2016.

But many of the senators present at Wednesday’s closed-door summit, which was held at the Washington Nationals’ baseball stadium, are rather less keen to be associated with the White House as they fight to hold their seats this year, according to campaign staff – and judging by recent public rifts.

Louisiana senator Mary Landrieu, one of seven candidates running to hold Democratic seats seen as vulnerable in states taken by Mitt Romney in 2012, last week described the Obama administration as "short-sighted, misguided and irresponsible" during a clash over flood insurance. She also failed to appear at an event with Obama in New Orleans, a perceived snub aides claim was merely due to a scheduling conflict but is symbolic of the awkward policy dance facing moderate Democrats running in Republican states.

Senators Mark Begich and Mark Pryor, who are running for re-election in two other red states, Alaska and Arkansas, helped torpedo their fellow Democrats’ attempt to pass new gun control legislation by voting against it last summer. Kay Hagan of North Carolina also avoided being seen with the president when he made a trip to her state last month.

Democratic campaign strategists make no apologies for putting distance between vulnerable candidates and the president on a host of issues from Obamacare to energy policy.

“Every time the opposition points out a difference between these candidates and the president they are helping them in these states,” said one Democratic operative.

Just how tough this election cycle is for the Democrats becomes clear when the 36 Senate seats up for grabs are grouped according to party control and polling numbers.

The DSCC fears it could lose seven of the 21 currently Democratic seats that it must fight to hold – South Dakota, West Virginia, Montana, Arkansas, Louisiana, Alaska and North Carolina – but is only hopeful of taking two from Republicans: Georgia and Kentucky.

The electoral math is even bleaker in the House of Representatives, where Democratic National Committee chair Debbie Wasserman Schultz recently admitted she could not “confidently predict” that her party would close the 32-seat gap needed to take back control of the lower chamber.

Party officials are privately urging donors to consider switching some funding away from the almost impossible House campaign and to concentrate their money and efforts on protecting the Senate and avoiding complete Republican domination of Congress.

Though it is significantly behind in opinion polls in several key races, including South Dakota and West Virginia where sitting Democrats are retiring, the party puts a brave face on the challenge by pointing out that the Republicans would have to triumph in almost all the competitive races in order to secure the majority.

“They have to win eight out of nine of the competitive races to take the majority. These are going to be very tough races, but they are going to have to have an almost perfect score,” Justin Barasky, the Democratic Senate Campaign Committee’s national press secretary, told the Guardian.

Democrats could also get some boosts in the coming weeks from the appointment of an interim senator in Montana and potentially bitter primary fights among Republican rivals in a number of states.

The Montana appointment was triggered by the White House’s decision to appoint the retiring senator Max Baucus as US ambassador to China – a move the party privately hopes will allow the state's Democratic governor to appoint their favoured candidate before the midterms, thereby securing that candidate an incumbent’s advantage.

Democrats also hope that Republican primaries in Kentucky, Alaska and North Carolina will distract their opponents and pull moderate candidates to the right in ways that may alienate floating voters come the general election.

In Kentucky, Senate minority leader Mitch McConnell’s campaign spent about $5m last year, according to filings with the Federal Election Commission, and may have to expend more energy fighting a challenge from the Tea Party wing of his party than fighting the Democratic candidate.

Internal Democratic party polling seen by the Guardian suggests the GOP leader may indeed be vulnerable - it shows him with a net job approval rating of -27% compared with +9% in 2008.

Ousting McConnell would be an audacious Democratic coup, and not one easily accomplished. He has an unparalleled reputation for raising campaign funds and can draw on support from outside interest groups that the DSCC acknowledges cannot easily be matched.

"At the committee level we have consistently out-raised the NRSC [National Republican Senatorial Committee] which is important because we are going to be outspent on TV by the outside groups, like the Koch-brothers fueled Americans for Prosperity," said Barasky.

Americans for Prosperity, a conservative political advocacy group, is thought to have spent almost $30m backing Republican candidates – House and Senate – already this election cycle, and recently paid for at least $1m worth of new airtime for ads against Senators Pryor and Hagan.

Democrats face a common challenge of midterm election due to the propensity for low turnout and are spending millions on voter registration drives in cities such as Atlanta, where an estimated 400,000 African Americans are unregistered.

Whether Obama and Clinton get further involved at Wednesday's strategy session or not, there are few in the party with any illusions about how important it is to hold onto the Senate, or how difficult doing that will be.

"We know the hand we have been dealt: we are defending more than twice as many seats as they are and are doing it on their turf,” Barasky said.

“The Democratic Senate is a good stop on the Republican House right now and the prospect of an entirely Republican-controlled Congress is very scary to people.”